She managed to raise the alarm, before one of the offenders yanked her hair.

The other offender filled a Manchester United duvet cover with cigarettes, before the duo fled on foot in the direction of Windleshaw Street and Ince Green Lane.

One man was described as white, in his early 20s, around 5ft 8ins tall and of slim build.

The second was said to be white, 5ft 8ins tall, in his mid 20s and of medium build.

Both men wore dark clothing and balaclavas.

Det Con Andrew Hill, of Greater Manchester Police's Wigan borough, said: “This was a violent robbery and it’s shocking that a woman was subjected to this attack whilst doing her job.

“The actions of these men have left her understandably shaken and I would urge anyone with information that could help our investigation to contact police.

“The red Manchester United duvet cover used in this robbery is very distinctive and would have made the offenders stand out. If you were in the area around the time of the robbery and remember seeing anything suspicious, please get in touch so we can find the men responsible.”

Anyone with information is asked to call the police on 101, quoting incident 2049 of February 2, or Crimestoppers, anonymously, on 0800 555 111.